2013 LX 570 AHC issue - Code C1763 and Possible Missing AHC Relay?

[LFODLX570]

Hoping someone here can lead me in the right direction. I'm having some issues with our family hauler 2013 URJ200 with 175K. We lost AHC system close to home luckily - limped back and plugged in techstream. Dreaded C1763 abnormal pump oil pressure showed up.

Here is the process I've gone through to diagnose/fix it:
- I hooked up 12 volts to the AHC pump in an attempt to jog it back to life with no movement.
- I inspected the fuses which all looked fine
- Discovered there is no AHC relay in the fuse box despite the cover showing their should be (see pictures below). Are all 2013s like this? Found a picture of a 2011 lx570 fusebox that had the same configuration as my fusebox cover. Anyone have a picture of their 2013 fusebox?

-Decided to install a new OEM AHC pump and globes. Original pump was heavily corroded (started life as a Maine truck) and globes were over 50K old. Poured a metal can's worth of fresh AHC fluid in the resevoir.
- Said a little prayer and started the truck - no pump motor movement and the C1763 returning immediately after clearing in TechStream.

I've read hear that sometimes a new AHC pump needs to be primed before the C1763 code clears. My though was to energize it 12V to get it started, but I also dont want to fry anything

Do you guys have any suggestions on getting the truck back in order?


Here are the current readouts from tech stream:

and...

 

[grinchy]

Yes, the new pump will need to be primed. Sadly it’s been a few years since this came up and I forget what has worked to prime in the past. Keep searching, or maybe spin thru thru the sticky AHC thread

 

[grinchy]

Here’s a post with some priming info from the sticky thread
Post in thread 'LX570 AHC “Basics” - Added as sticky thread for AHC Issues'
LX570 AHC “Basics” - Added as sticky thread for AHC Issues - https://forum.ih8mud.com/threads/lx570-ahc-basics-added-as-sticky-thread-for-ahc-issues.1053154/post-16028678

 

[LFODLX570]

Here’s a post with some priming info from the sticky thread
Post in thread 'LX570 AHC “Basics” - Added as sticky thread for AHC Issues'
LX570 AHC “Basics” - Added as sticky thread for AHC Issues - https://forum.ih8mud.com/threads/lx570-ahc-basics-added-as-sticky-thread-for-ahc-issues.1053154/post-16028678

Thanks, I'll give it a try today and report back!

 

[LFODLX570]

Update:

I tried priming the new AHC pump by connecting it directly to a car battery. The pump actuated and it looks like it got some oil into the system. When I tried jumping the original pump using the same process there was no accuation. I re-attached the connectors and tried starting the vehicle but the C1763 code came back. I think I am going to try doing the same thing while monitoring pressure levels in Techstream to get some more data points.

Will continue to look through the threads here for new ideas of what to try.

 

[grinchy]

You can try to PM a few of those that have replaced. What I read yesterday was to give it a few short on off cycles, if you got some fluid movement it seems likely it is primed or about to prime

 

[LFODLX570]

Positive update!

After replacing the AHC Pump, four globes, resetting fault codes in Techstream, and attempting to prime the pump by powering 12V direct from a spare battery - we were still getting the C1763 error. Digging a little deeper, we confirmed there was continuity between the fuse box and the AHC pump. It is probably not the original fuse box (see a seperate post on that subject here).

I invited my neighbor over and we started attempting to trace the issue. First we dug into the ebay wreck 2013 lx570 fuse box I purchased and sure enough it looked like this:

When my actual fuse box looks like this:

After showing continuity between the blue relay to the left of the red circle and the ACH connector, and the last red fuse all the way to the right (in the pic above) we decided to remove them completely and see what happened. Upon startup, like a phoenix rising from the ashes, the truck starts to come off its bumpstops. I can hear the pump running and the vehicle eventually settles in high mode, but this time it doesnt leak down in high mode like it had been doing before pump failure. The truck was able to cycle between heights quickly. I bled the system, buttoned up the body work and took her for a 40 min test drive. The ride was excellent which is not suprising considering it had just had a complete flush and bleed and new globes (original shocks). We will see what the future holds (the stereo sounded a little quiet on the test drive lol), but we are back in business!